Metal lithium powder is widely applied to the fields of preparing lithium alkylide, catalysts, additives, and lithium cells, etc. As the metal lithium can hardly be pulverized into powders by conventional pulverization methods such as mechanical pulverization due to its high reactivity, larger viscosity, lower melting point (180.5° C.) and lower density (0.534 g/cm3), a melt-dispersion method is currently prevalently adopted to prepare the metal lithium powder. The metal lithium melt-dispersion method is a method of heating the metal lithium in a dispersant, stirring at a high speed to disperse the lithium droplets, then cooling, centrifuging or filtering, rinsing, and drying to form lithium powder. The lithium powder prepared in this method is in a spherical shape; during the preparing process, a high boiling-point hydrocarbon oil, a low boiling-point hydrocarbon oil for rinsing, a relatively high operation temperature of nearly 200° C., and an inert protection atmosphere are needed; such that this preparation method has problems such as a high preparation cost, a low preparation efficiency, being highly demanding on equipment, and inability to prepare a non-spherical lithium powder, etc.
Ultrasonic pulverization is an approach of cavitating a liquid by leveraging the dispersion effect of ultrasonic in the liquid to thereby pulverize the solid particles or cell tissues in the liquid. CN107297507 discloses a method of preparing a metal lithium powder by ultrasonically pulverizing the metal lithium in an ion liquid at a temperature higher than 100° C. However, the ion liquid leveraged in this method has a high liquid viscosity and a high boiling point; moreover, the operating temperature reaches 100° C. above; at this point, the cavitation effect of the ultrasonic is weak, and the efficiency of converting the ultrasonic energy to the mechanical pulverization energy is low, such that it is hard to achieve a desired metal lithium pulverization effect and efficiency.